Because of the well-known advantages of reinforced composites (i.e., high strength to weight ratio, controlled thermal expansion), it would be desirable to use such composites in high temperature applications, for example, in parts of turbine engines. However, since the matrix polymers employed in such composites normally degrade at temperatures within the range of 250.degree. to 400.degree. C., they have not enjoyed wide application. One solution for extending the applicable temperature range of such composites, analogous to the solution employed for metal structures, would be the use of ceramic coatings--to provide oxidation protection and to act as an insulative thermal barrier. Unlike metal surfaces, it is often difficult to form acceptable ceramic coatings on composite surfaces, i.e., coatings with good adherence and which do not spall in service. A potential solution, described in U.S. Pat. No. 3,179,531, is the incorporation of refractory materials intermixed into the top layer of the composite, i.e., the surface to be coated, such that refractory material is firmly embedded in that surface and acts to form a bond with the refractory material which is subsequently sprayed thereon to the desired thicknesses. Another solution is shown in U.S. Pat. No. 3,892,883, wherein adherence is improved by utilizing two intermediate layers--the first layer being copper/glass, which is adherent to the composite surface; and the second layer being a nickel aluminide, which bonds well both to the copper/glass layer and to the subsequent plasma-sprayed refractory layer. Yet another solution is shown in U.S. Pat. No. 4,388,373 wherein an adherent intermediate layer is flame sprayed onto the plastic surface--using a powder composition consisting of a mineral powder admixed with small amounts of nylon and expoxy powders. None of these processes has gained wide acceptance in the industry--either because ceramic coatings so-produced are nevertheless suboptimal and/or because the method involved is unduly cumbersome and costly.